The present invention relates to transparent articles having an anti-reflection surface and method of fabricating a transparent anti-reflective structure.
Transparent electronic display screens made of glass or plastic, such as cell phone screens, computer screens, and TV monitors including liquid crystal displays (LCD), are difficult to view as external ambient light reflects off their surface. Researchers and engineers have worked on several techniques to minimize this reflection using various screen surfaces, including anti-glare and anti-reflection screens.
Most anti-glare screens use a treatment on their top surface to diffuse the reflected light from external lighting sources. This treatment consists of laminating a matte surface layer having a micrometer-scaled roughness to the screen surface. As light hits the rough surface, it bounces off at different angles, which reduces the intensity of light reflecting off of the surface and hitting a viewer's eyes. While this reduces the intensity of light, it does, however, leave a hazy image of the reflection which may block the onscreen image. This treatment also distorts the image generated by the LCD.
Alternatively, anti-reflection screens do not have a rough matte anti-glare surface. Rather, anti-reflection screens use an anti-reflective coating material, such as magnesium fluoride (MgF2), to reduce the reflected light by lowering the refractive index of the surface of the display panel to more closely approximate that of air. This process is known as index matching. This reduces the reflection and refraction of ambient light as it hits the surface of the display screen. Compared to anti-glare screens, the smooth gloss finish of an anti-reflection screen results in a crystal clear image. Anti-reflection screens also have a wider view angle and produce images with higher contrast and richer colors. However, there are very few transparent coating materials available with a low refractive index for index matching. Furthermore, it is difficult to find a transparent coating material to match the particular range of most glass and polymers.
Thus, there is a need for transparent articles having anti-reflection surfaces for devices such as electronic display screens, optical sensors, and solar cells.